Bench Test Procedure for Hydraulic Piston Pumps {4306, 5070} Caterpillar

Off-Highway Truck/Tractor

785G (S/N: RTL1-UP)

Introduction

© 2017 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law. Information contained in this document is considered Caterpillar: Confidential Yellow.

This Special Instruction includes test procedures for piston pumps. This Special Instruction also provides specifications. The technician should have a good understanding of hydraulic piston pumps. The technician should be educated in the operation of the hydraulic test bench. The test benches in this document are available through the Caterpillar Service Tool Division. Gather all necessary tooling before you need to hook up the pump. Some of the required tooling appears in a table at the end of this document. There are many possible variations of tooling that could be used. Not every possible variation can be listed.

For technical questions when using this document, work with your Dealer Technical Communicator (TC).

To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) interface.

Canceled Part Numbers and Replaced Part Numbers

This document may not include all Canceled part numbers and replaced part numbers. Use NPR on SIS for information about Canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Safety

Illustration 1	g02139237

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Personal injury or death can result from improperly checking for a leak. Always use a board or cardboard when checking for a leak. Escaping air or fluid under pressure, even a pin-hole size leak, can penetrate body tissue causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

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Pump test pressures in this guideline may exceed the normal operating range of the hydraulic test hoses utilized when connecting the tested pump to the test bench. However, the order of magnitude of these pressures is significantly below the burst strength of the Caterpillar "XT6" product. High pressure oil can escape through improperly assembled hoses and fittings. High pressure oil can also escape through poorly maintained hoses and fittings. High pressure oil may also leak through hose that has become damaged over the life of the hose due to the pressure levels that occur during test bench operation. Personal injury or death can result from improper hose & fitting inspection or improper hose replacement procedures. Escaping fluid under pressure can penetrate body tissue causing serious injury, and possible death. Thoroughly inspect all testing hoses, fittings, and quick disconnects prior to any testing operation. Check the assembly date tag or hose assembly log date for a hose life indicator. Replace all Test Bench hoses at a minimum of every 2 years or earlier if the hose or fittings appear to be damaged.

Summary

This procedure is specific to the type of pump and the type of control. Refer to the test specifications and the tooling at the end of this document.

Note: A paper copy of this document may not be the latest version. Go to the Service Information System (SIS) to view the latest version.

References

Connections for the Caterpillar Hydraulic Test Center

Illustration 2	g01178572
Connections for the test center (1) Flow control for discharge (2) "F3" flow meter inlet (3) "F4" flow meter inlet (4) Oil supply from the auxiliary pump (5) "F3" inlet for the flow meter with flow limiter (6) "F3"outlet for the flow meter with pressure control (7) Load sensing pressure (8) Signal pressure (9) "F4" outlet for the flow meter (10) Return to tank (11) Connections for case drain (12) Oil supply

Illustration 3	g01178573
Control and gauges for the test center (13) Meter for speed and torque (14) Gauge for signal pressure (15) Control for signal pressure (16) Pressure gauge for auxiliary pump (17) Auxiliary pump flow (18) "F3" Discharge pressure gauge (19) "F3" Discharge flow (20) "F4" Discharge pressure gauge (21) "F4" Discharge flow (22) Auxiliary pump flow control (23) "F3" Margin pressure (24) "F3" Load control for discharge pressure (25) "F4" Load control for discharge pressure

Connections for the Caterpillar Hydraulic Test Bench

Illustration 4	g01178574
Connections for the test bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil supply

Illustration 5	g01178575
Connections for the test bench (28) "Flow meter 2" loop (29) "Flow meter 1" loop (30) "Flow meter 2" outlet (31) Signal pressure line (32) "Flow meter 2" inlet (33a) "Flow meter 1" outlet (33b) Auxiliary Oil supply outlet (34) Auxiliary Oil supply inlet (35) "Flow meter 1" inlet

Illustration 6	g01178576
Control and gauges for the test bench (36) Auxiliary Oil supply pressure (37) Signal pressure (38) Control for signal pressure (39) "Flow meter 1" discharge pressure (40) Control for auxiliary Oil supply pressure (41) "Flow meter 2" discharge pressure (42) Control for the auxiliary oil supply (43) "Flow meter 2" discharge flow (44) Discharge flow for auxiliary pump (45) "Flow meter 1" discharge flow (46) "Flow meter 1" load control (47) Speed and direction control (48) "Flow meter 2" load control

Port Locations

Illustration 7	g06184462
Pump port locations and adjustments (49) Case drain port (50) Electrical connector for control solenoid (51) Case drain port (52) Adjustment screw for pressure cutoff (53) Suction port (54) Case drain port (55) Minimum displacement plug (56) Discharge port

Illustration 8	g06184472
Hydraulic schematic (49) Case drain port (50) Electrical connector for control solenoid (51) Case drain port (52) Adjustment screw for pressure cutoff (53) Suction port (54) Case drain port (56) Discharge port

Pump Setup

Note: A power supply will be required to operate the control solenoid on this pump. The power supply must deliver 0 mA to 1400 mA with an infinite setting in that range.

1. Mount the pump with case drain port (49) facing upward. Connect the oil supply suction hose from the oil supply on the test bench to suction port (53).

2. Connect a one-inch high-pressure "XT6 ES" hose from the pump discharge port (56) to the flow meter inlet on the test bench.

3. Connect a one-inch high-pressure hose from the outlet of the flow meter on the test bench back to the tank.

4. Fill the pump case with oil. Pour oil directly into a case drain port (49) until the case is full.

5. Connect an in-line flow meter to the top Case drain port (49). Direct the oil from the in-line flow meter back to the tank.

6. Purge all air from the suction line. Loosen the suction hose at the pump until oil leaks from the connection. Tighten the suction hose.

7. Connect a power supply to the electrical connector for control solenoid (50) to operate the electronic control valve.

8. Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pump. The correct direction of rotation will also be in the test specifications. The direction of rotation is viewed from the input shaft end. Visually check the pump for proper rotation.

Test Procedure

Note: The steps in the procedure correlate with the steps in the test specification tables according to your specific part number.

The contamination level of the hydraulic oil in the test bench should be ISO 16/13 or better. The oil in the test bench should be one of the following.

• SAE 10W at 50 °C (122 °F) or

• Mobil DTE-11 at 46 °C (115 °F)

1. This step will check hydraulic connections and pump integrity.

   Start rotating the pump according to the input speed in Step 1 of the Test Specifications. Increase the signal current to electrical connector for control solenoid (50) to the value in Step 1 of the Test Specifications. Increase the discharge pressure to the value in Step 1 of the Test Specifications. Listen for abnormal noise. Verify flow from the pump. Verify that all the connections are not leaking. Check for leaks around shaft seals and control valves.

   Run the pump for at least 5 minutes to raise the temperature of the oil and purge the system of air.

2. This step will verify the maximum displacement of the pump and the end point of the electronic control.

   Slowly increase the pump input speed according to the value in Step 2 of the Test Specifications. Verify that the discharge flow matches the value in Step 2 of the Test Specifications. The pump may not be mechanically feasible if the discharge flow does not match the value in Step 2 of the Test Specifications.

3. This step will verify the minimum displacement of the pump and the starting point of the electronic control.

   Reduce the signal current to the value in Step 3 of the Test Specifications. This point is the start of the electronic control. The pump is at the start of upstroke. Discharge flow should be at minimum at this point.

4. This step will verify the electronic control cut-off function.

   Reduce the signal current to the value in Step 4 of the Test Specifications. This point simulates a loss of electronic control signal condition. The pump should be fully stroked at this point. Verify that discharge flow matches the value in Step 4 of the Test Specifications.

5. This step will measure the volumetric efficiency of the pump.

   Increase the signal current to the value in Step 5 of the Test Specifications. Increase the pump discharge pressure to the value in Step 5 of the Test Specifications. Measure the case drain using the in-line flow meter. If the case drain flow is higher than the value in Step 5 of the Test Specifications, the pump may need to be internally inspected.

6. This step will verify the setting of the pressure cutoff.

   Increase the discharge pressure to the value in Step 6 of the Test Specifications. The pump should destroke and flow should drop to minimum. If the flow does not drop to minimum at this pressure, the pressure cutoff should be adjusted. Turn Adjustment screw for the pressure cutoff (52) until the actual pressure cutoff value is equal to the value in Step 6 of the Test Specifications. Turn Adjustment screw for the pressure cutoff (52) clockwise to increase the pressure cutoff. Turn Adjustment screw for the pressure cutoff (52) counterclockwise to decrease the pressure cutoff.

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Reduce all signal currents, pressures, and input speed to zero. Allow the component to cool. Remove the component from the test bench. Drain the oil from the pump. Cap or plug all the ports.

Test Specifications

Test Bench Tooling